Mercedes-Benz Unimog U4023 Hellgeth concept review

What is it?

In essence, this is a Unimog U4023. But it is also rather more than that, having received the careful attention of Daimler/Mercedes-Benz Special Trucks Division in partnership with Hellgeth Engineering. The result of that particular Avengers-style collaboration is claimed to be the ‘most luxurious and powerful Unimog’ ever built, although it remains a prototype in the strictest sense.

Think of it as a sports lorry: the hypercar of Unimogs, created to demonstrate a more road-focused ‘Mog. It is due to undertake proper real-world road testing with a customer based in the US, once the emissions rules and import documents have been sorted. We cannot reveal who the customer is, but he will doubtless return… to Germany to pick it up when the paperwork is complete. Cough.

Photography: Alex Tapley [main]/manufacturer [below]

Understood. Possibly. So what has changed?

A fair amount, although an off-road-spec Unimog is hardly under-equipped in standard form. It retains portal axles, which position the differential crown above the wheel centreline, while reduction gears within the hubs provide immense torque multiplication for climbing the north face of the Eiger vertically and/or navigating the Arndale Centre. The hubs can alternatively run at 1:1, relying solely on the Unimog gearbox and its exceptionally low-range ratios.

There are mechanical differential locks throughout, heavy-duty components everywhere, a chassis that articulates through its middle during serious off-roading, enormous tyres and aerodynamics comparable with the blunt end of Dorset.

The concept adds further embellishments. Matte grey paint covers new body panels intended to inject some style into the Unimog’s steadfastly workwear-like appearance: more Calvin Klein than Carhartt. It gets a smart roof rack, albeit one that is practically impossible to load given that it sits 3.7 metres above the ground, the world’s chunkiest roll hoop, a substantial light bar, front and rear LED lamps, digital mirrors borrowed from a modern lorry, and skid plates seemingly taken from a battleship.

Want to lower the tyre pressures without leaving the cab? Central tyre inflation means your hands stay clean. There is also a 165-litre fuel tank, expandable to 235 litres or beyond if desired. That makes for a casual £350 fill-up.

You may need the capacity, because while most Unimogs use large four-cylinder engines, this one has one of the less common straight-sixes, tuned and fettled by Hellgeth to make it decidedly not-a-U4023. It is a 7.7-litre version of Mercedes’ OM936. Yes, that is a little over 1.1 litres per cylinder. Output is ‘only’ 300bhp, accompanied by 1,033lb ft of torque.

For a vehicle weighing more than ten tonnes, the power-to-weight ratio is… well… approximately that of an original Renault 4. Yet its gearing and sheer mass mean it could plough through the frozen wastes of Hell if necessary. Speed is not the point here; invincibility is. It could probably tow the Earth off its axis, even while off-road.

What about the inside? It is supposed to be a luxury vehicle.

And it is, in a fashion. Define ‘luxury’ against the usual Unimog interior and it certainly qualifies, though Maybach engineers are unlikely to be having sleepless nights. There are now four electrically operated, air-sprung seats trimmed in quilted leather. They are fundamentally the same seats fitted to a regular ‘Mog, merely enhanced with extra garnish: comfortable, rather than especially sophisticated.

There are genuinely only four seats in a cab the size of a small flat, with the vehicle’s centre occupied by a quilted-leather engine cover resembling a coffin. LED lighting is fitted, along with further quilted leather on two roof panels, but this is not a comprehensively reimagined Unimog cabin.

That becomes clear when you take hold of the huge steering wheel, identical to that in the normal model. It lies almost horizontally, angled towards an overtly utilitarian collection of driver instruments. The centre console is standard issue too: plastic, and full of buttons. There are controls for low range, electric windows and assorted lighting, plus a rotary controller for the three differential locks. Everything is practical and plain, with a conspicuous absence of anything knurled.

Still, that is not its intended role, and excessive poshness might strip away part of its character. It is undeniably enormous, though: you sit considerably higher than in any production SUV and look HGV drivers straight in the eye.

What is the Unimog like to drive?

A standard ‘Mog in this guise is not one of the utility versions, so it cannot carry the various attachments or have its steering wheel switched from left to right in a field, as some of the ultimate working models can. Instead, this concept prioritises maximum off-road ability, and almost nothing has changed dynamically either to diminish that capability or sharpen its road manners.

Its tyres are more road-oriented than those on agricultural ‘Mogs, which helps, but weight, height and compliant suspension remain the overriding factors. Steering effort is moderate, while the ratio is extraordinarily slow, which is useful in something like this: no one wants to tip one into a bend with an ill-timed flick of the wrists. At roundabouts, you will wind on far more lock than expected, while carrying too much speed brings dramatic, precipitous body lean.

And yes, the blind spots are everywhere. Digital cameras provide useful assistance, however. One is mounted in the headlining to offer a direct rearward view, while the side displays show the rear quarters as well as the space below hip level, allowing you to spot concealed cyclists or VW Polos. In town, it is absurdly entertaining: people genuinely cheer as it passes. Odd.

The gearbox is an eight-speed electro-pneumatic automatic, with the pause-shift-engage character familiar from vehicles that haul multi-tonne trailers. It is unhurried and restricted to around 56mph, although you would probably not want to travel much faster anyway. Braking is dependable but requires forethought: you drive it with your eyes raised, like an HGV driver, looking far ahead and preparing to slow on your own terms rather than somebody else’s. Then again, few people pull out in front of it. Indeed, we have yet to encounter a car that makes other motorists more respectful.

So what is the deal – can anyone buy one?

For now, this Unimog remains strictly a ‘concept’. If enough demand emerged, though, a very limited production run could be considered. Pricing is uncertain, but you should not expect much change from three quarters of a million Euros, roughly £650k. Hellgeth can supply the engine in any case, and most of the remaining components could be sourced by anyone with sufficient funds and determination, so it is not vapourware in the strictest sense.

One point is guaranteed: as a road car-slash-sports lorry, it draws more attention than any blinged-up G-Wagen or Revuelto. Arrive at Casino Square in this and you will command every eye in the area. Along with six parking spaces.